1. Technical Field
The present invention is concerned with motors having a bearing mechanism, and with sleeve units for the motors, and in particular relates to technology for manufacturing such sleeve units.
2. Description of the Related Art
Recording-disk drives for storage devices such as hard disks are conventionally furnished with a spindle motor for rotationally driving the recording disk(s). (Such spindle motors will be referred to simply as “motors” hereinafter). One motor bearing mechanism that has been adopted in recent years is the hydrodynamic-pressure employing bearing mechanism. To employ hydrodynamic pressure, such bearing mechanisms are configured with thrust and radial bearing sections in between the motor shaft, and a sleeve into which the shaft is inserted.
In a publicly available example of such technology, a cylindrical housing attached to the outer periphery of a sleeve is anchored into a bracket, and a bearing mechanism employing oil dynamic pressure is constituted in between the sleeve and the housing (the two of which will together will be referred to as a “sleeve unit” hereinafter), and a rotor including a shaft that is inserted into the sleeve unit.
In attaching the sleeve housing to the sleeve in this sort of sleeve unit, in order to get the axial separation between the upper endface of the housing and the lower endface of the sleeve to meet the design specification for the separation, the two endfaces must be precisely aligned.
Further, in order to prevent the surfaces of the bearing-constituent sleeve from warping in manufacturing these sleeve units, ordinarily a slight interspace is left between the sleeve and the sleeve housing, and the sleeve is inserted into the housing and adhered to the housing via an adhesive.
With this method of manufacturing the sleeve units, inserting the sleeve into the sleeve housing leads to the adhesive being pushed out of the housing, running the risk that the adhesive will stick to sleeve, housing, bearing-thrust-plate and other surfaces where it is not needed, or end up contaminating the manufacturing jig.
Moreover because the gap between the sleeve and the shelve housing is extremely narrow, to prevent the sleeve and the housing from being damaged when the sleeve is inserted into the housing, the sleeve must be inserted smoothly without excess force being imparted to the sleeve.